Facilitation of muricide in rats by cholinergic stimulation of the lateral hypothalamus.

The effect of cholinergic stimulation of the lateral hypothalamus on muricide in rats was evaluated in two experiments. In Experiment 1, injections of the cholinergic agonist carbachol (5.0-20.0 micrograms) were found to facilitate muricide in rats that spontaneously killed mice. In Experiment 2, rats were induced to kill mice by food deprivation and then stimulated with carbachol (2.5-5.0 micrograms). Facilitation of muricide was found to be coincident with increased scores on a handling difficulty (irritability) scale for the majority of rats. These results suggest that facilitation of muricide by cholinergic stimulation of lateral hypothalamic areas may be related to increases in irritable aggression.